The present invention relates to an insulated structure and a method for insulating a structure by substantially eliminating air infiltration.
With the public awareness of our ever decreasing supplies of fossil energy and the increasing number of people utilizing these diminishing fuels, it has become apparent that energy conservation measures must be taken in order to prolong the availability of fossil fuels for as long a period of time as possible. The matter has become so important that federal legislation has established a comprehensive national program for research and development of all potentially beneficial energy sources and conservation technologies.
One of the greatest demands upon the use of fossil energy is the heating and cooling of inhabited structures such as residences and commercial buildings. Tax incentives are offered to individuals who will increase the insulation in their homes. The problems with heating or cooling a structure are twofold. First is the problem of air infiltration into and out of the structure and second is the rate of heat transfer between the inside and the outside of the structure. If these two factors can be controlled, a tremendous reduction in the cost of heating or cooling a structure would result.
In the construction of a structure, particularly a residential structure, most commonly the skeleton frame of the structure is erected, an interior grade material, such as, for example only, panels of sheetrock, is attached to the interior side of vertical wall studs on the periphery of the structure and an exterior grade material, such as, for example only, panels of wallboard, is attached to the exterior side of the vertical wall studs on the periphery of the structure. Hereinafter, the terms "sheetrock" and "wallboard" will be used to indicate "interior grade material" and "exterior grade material" respectively. Electrical cables encased in metal sheaths and pipes for various uses are routed through the wall space formed between the sheetrock and the outer wallboard by simply drilling a hole through the vertical studs and inserting the sheath or pipe through the hole. Obviously, any air which infiltrates the space between the inner sheetrock and the outer wallboard travels in the wall space through the holes formed for the pipes and electrical cable sheaths to any area where it can escape to the inside of the structure through electrical outlets, cracks caused by imperfect construction, and the like. Further, in the erection of these structures, the wallboard that is being or has been applied to the vertical studs to form the external walls of the structure is often damaged. The wallboard panels are composed of a relatively soft material which is easily damaged by accident such as dropping it or striking objects against it, thus, forming or causing a crack or hole in the material. These cracks and/or holes allow a great deal of air to enter the wall space between the sheetrock forming the inside wall and the wallboard forming the outside wall and allow penetration of that air into the interior of the structure. Further, when the wallboard is attached to the outside of the vertical studs on the periphery of the structure, it is attached as panels in abutting relationship to each other. This abutting relationship cannot provide an airtight joint and air is able to penetrate the interior of the wall through these abutting panels of wallboard.
In addition, the rate of heat transfer between the interior and the exterior of a structure is dependent upon the type and quality of construction and the amount and type of insulation used during construction. The poorer the quality of construction and the use of construction techniques which do not allow protection from heat transfer, such as dead airspaces, contribute to an increased rate of heat transfer and a corresponding increase in the consumption of energy required to heat or cool the interior of a structure.
Further, if the outer wall is sealed airtight, the air in between the outer and inner walls carries the moisture available inside the structure and if the temperature differential is sufficient, the moisture condenses to form water between the inner and outer wall thus reducing the insulating capability of the ambient air space and causing damage to the building structure.